[2/3] EDAC, pnd2: Conditionally unhide/hide the P2SB PCI device to read BAR.

[2/3] EDAC, pnd2: Conditionally unhide/hide the P2SB PCI device to read BAR.

[Qiuxu Zhuo]

On Deverton server, the P2SB PCI device(DEV:1F, FUN:1) is used by multiple
device drivers, if it's hidden by some device driver(e.g. i801 I2C driver,
the commit <942469303> unconditionally hides the P2SB PCI device wrongly)
it will make the pnd2_edac driver read out an invalid BAR value 0xffffffff
and then fail on 'ioremap()'.

Therefor, store the presence state of P2SB PCI device before unhiding
it for reading BAR and restore the presence state after reading BAR.

Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
---
 drivers/edac/pnd2_edac.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/edac/pnd2_edac.c b/drivers/edac/pnd2_edac.c
index 2b16b95..89cdd9a 100644
--- a/drivers/edac/pnd2_edac.c
+++ b/drivers/edac/pnd2_edac.c
@@ -236,12 +236,23 @@ static u64 get_sideband_reg_base_addr(void)
 {
 	struct pci_dev *pdev;
 	u32 hi, lo;
+	u8 hidden;
 
 	pdev = pci_get_device(PCI_VENDOR_ID_INTEL, 0x19dd, NULL);
 	if (pdev) {
+		/* Unhide the P2SB device, if it's hidden */
+		pci_read_config_byte(pdev, 0xe1, &hidden);
+		if (hidden)
+			pci_write_config_byte(pdev, 0xe1, 0);
+
 		pci_read_config_dword(pdev, 0x10, &lo);
 		pci_read_config_dword(pdev, 0x14, &hi);
 		lo &= 0xfffffff0;
+
+		/* Hide the P2SB device, if it was hidden before */
+		if (hidden)
+			pci_write_config_byte(pdev, 0xe1, hidden);
+
 		pci_dev_put(pdev);
 		return (U64_LSHIFT(hi, 32) | U64_LSHIFT(lo, 0));
 	} else {

[2/3] EDAC, pnd2: Conditionally unhide/hide the P2SB PCI device to read BAR.

[Borislav Petkov]

On Mon, Aug 14, 2017 at 11:48:45PM +0800, Qiuxu Zhuo wrote:
> On Deverton server, the P2SB PCI device(DEV:1F, FUN:1) is used by multiple
> device drivers, if it's hidden by some device driver(e.g. i801 I2C driver,
> the commit <942469303> unconditionally hides the P2SB PCI device wrongly)

This is not how we quote commits in commit messages. Rather like this:

  9424693035a5 ("i2c: i801: Create iTCO device on newer Intel PCHs")

You can add

[alias]
        one = show -s --pretty='format:%h (\"%s\")'

to your .gitconfig so that when you do:

$ git one 9424693035a5

you get the proper format. You'll also need

[core]
        abbrev = 12

so that the commit hash is abbreviated to 12 chars.

I fixed it up now but pls do it properly next time.

Thanks.

[2/3] EDAC, pnd2: Conditionally unhide/hide the P2SB PCI device to read BAR.

[Qiuxu Zhuo]

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